Transcript PPT Format - HubbleSOURCE

Hubble Science Briefing:
25 Years of Seeing Stars with
the Hubble Space Telescope
March 5, 2015
Dr. Rachel Osten
Dr. Alex Fullerton
Dr. Jay Anderson
Hubble’s Insight into the
Lives of Stars Comes From:
 Better image clarity: no
atmosphere, no blurring means
higher spatial resolution
 Access to ultraviolet
wavelengths: not possible from
the ground
2
3
Outline
• Rachel Osten - cool stars
• Alex Fullerton - massive stars
• Jay Anderson – globular clusters
4
The UV spectrum of a Sun-like star
Hot gas (>10,000 K) means that many elements are ionized
Hotter than the visible surface of the star (Sun=5800 K)
Linsky & Wood 1994
5
The UV spectrum of a Sun-like star
B
r
i
g
h
t
n
e
s
s
Alpha Cen A
at higher spectral
resolution than
UV spectra from the
Sun!
Pagano et al. 2004
6
The UV spectrum of a Sun-like star
B
r
i
g
h
t
n
e
s
s
Linsky & Wood 1994
Dynamics of the atmosphere
7
The UV spectrum of a Sun-like star
B
r
i
g
h
t
n
e
s
s
0
200
400
600
800
0
200
400
600
800
Time (seconds)
The changing of a star’s intensity with time on these short timescales is due to heating
from flares occurring in the atmosphere of the star
Hawley et al. (2003)
8
Stars Blow Bubbles in Space
9
Stars Blow Bubbles in Space
Wood et al. 1995
10
Stars Blow Bubbles in Space
Wood et al. 2002
11
Stars Blow Bubbles in Space
Linsky et al. 2010
12
Outline
• Rachel Osten - cool stars
• Alex Fullerton - massive stars
• Jay Anderson – globular clusters
13
Massive Stars
Massive stars are also luminous stars.
1 Solar Mass
1 Solar Radius
1 Solar Luminosity
T = 5,800 Kelvin
Massive stars can be luminous because they are
• hot and compact
• hot and large
• cool and very large
4 - 300 (?) Solar Masses
3,000,000 Solar Luminosities
Temperature: 10,000 – 50,000 Kelvin
Radius:
2 – 15 Solar Radii
30 Solar Radii “Blue” supergiants
T = 7,500 – 3, 600 Kelvin
R =
80 – 8, 000 Solar Radii
“Red” supergiants
Image Source: kids.britannica.com
The Kelvin Temperature Scale: K =
5
( F - 32) + 273.15
9
14
15
R136
16
“P Cygni Profiles”
tell us about
mass loss via
a “stellar wind”
Space Telescope Imaging Spectrograph (STIS)
From a poster paper by A. Bostroem, N. Walborn, et al.
17
18
The Carinae Region: A Cauldron of Hot, Massive Stars
This spectacular montage was created to celebrate the 17th anniversary of Hubble’s deployment. It is composed of many
separate exposures with Hubble’s Advanced Camera for Surveys (ACS) and ground-based images from the Cerro Tololo
Inter-American Observatory (CTIO). For a fuller appreciation of its information content, explore the “zoomable” version:
http://hubblesite.org/newscenter/archive/releases/2007/16/image/a/format/zoom/
19
The Carinae Region: A Cauldron of Hot, Massive Stars
η Carinae
This spectacular montage was created to celebrate the 17th anniversary of Hubble’s deployment. It is composed of many
separate exposures with Hubble’s Advanced Camera for Surveys (ACS) and ground-based images from the Cerro Tololo
Inter-American Observatory (CTIO). For a fuller appreciation of its information content, explore the “zoomable” version:
http://hubblesite.org/newscenter/archive/releases/2007/16/image/a/format/zoom/
20
21
22
The Carinae Region: A Cauldron of Hot, Massive Stars
η Carinae
Trumpler 14
This spectacular montage was created to celebrate the 17th anniversary of Hubble’s deployment. It is composed of many
separate exposures with Hubble’s Advanced Camera for Surveys (ACS) and ground-based images from the Cerro Tololo
Inter-American Observatory (CTIO). For a fuller appreciation of its information content, explore the “zoomable” version:
http://hubblesite.org/newscenter/archive/releases/2007/16/image/a/format/zoom/
23
From the FGS Instrument Handbook
ine Guidance Sensor
“S-Curve” from an FGS scan of a
point source.
Introduction
The unprecedented pointing precision required by the Hubble Space Telescope (HST) motivated the design of
the Fine Guidance Sensors (FGS). These are large field of view (FOV) interferometers that are able to track the
positions of luminous objects in HST’s focal plane with ~1 millisecond of arc (mas) precision. The FGS can
also scan an object’s interferogram with sub-mas resolution. These capabilities enable the FGS to perform as a
high-precision astrometric science instrument and high resolution interferometer which can be applied to a variety of topics and objectives, including:
• Visual orbits for binary systems with separations as small as 10 mas. Detection of duplicity down to 7 mas.
• Measuring the angular size of extended objects.
• Relative astrometry at the 0.2 mas level (mV < 14.5).
• 40 Hz relative photometry (e.g., flares, occultations) with milli-mag accurac y
Transfer Mode Observing
In Transfer Mode the FGS scans an object to obtain its interferometric fringes with sub-mas resolution. This is
conceptually equivalent to imaging an object with sub-mas pixels. This makes the FGS ideal for studying binary
systems and extended objects over a large magnitude range (3.0 < m V < 16.0).
Binary Systems
Actual WFPC2 and simulated FGS Observations of a 168 mas binary system.
Although the binary in this example is clearly resolved by the
WFPC2 Planetary Camera (PC)
(Niemela et al. 1999), the FGS
could measure the component separation and relative brightness with
greater accuracy (± 1 mas v.
± 30 mas).
Simulated WFPC2 and FGS Observations of a 70 mas binary system.
Although a PC detection would be
questionable at 70 mas, the FGS
clearly isn’t challenged in detecting duplicity and measuring separations. Detections of duplicity
down to 7 mas are possible with
the FGS.
24
HD 93129A
Trumpler 14
Component A is also a binary!
Palomar Digital Sky Survey
HD 93129A
HD 93129B
ESO VLT: Aperture Mask with Adaptive Optics
Sana et al. 2014
Astrophysical Journal Supplement
European Southern Observatory Science Release 0947
Very Large Telescope + Multi-Conjugate Adaptive Optics Demonstrator
25
NGC 3603
HST/ACS
26
Outline
• Rachel Osten - cool stars
• Alex Fullerton - massive stars
• Jay Anderson – globular clusters
27
Plan
(1) Globular Clusters before HST
(2) Globular Clusters with HST
(3) Globular Clusters with 25 years of HST
28
Globular Clusters
• “Textbook” simple stellar populations
– Formed stars early
– Single cloud, single metallicity, single age
– Not large enough to self-enrich
– Continue orbiting in spheroid of Galaxy
• Perfect fossil
laboratories
to evaluate
stellar evolution
GC
GC
GC
GC
GC
NGC4013(NOAO)
29
Central
Field
project-nightflight.net
ω Centauri
Early Release
Field
30
http://hubblesite.org/newscenter/archive/releases/2010/28/ 31
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 32
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 33
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 34
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 35
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 36
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 37
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 38
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 39
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 40
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 41
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 42
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 43
What Astronomers see…
http://hubblesite.org/newscenter/archive/releases/2010/28/ 44
What Astronomers see…
3) Red Giant
Branch
4) Horizontal
Branch
5) White
Dwarf
Sequence
1) Main
Sequence
2) SubGiant
Branch
http://hubblesite.org/newscenter/archive/releases/2010/28/ 45
Easy to identify stars…
RGB
HB
BSs
SGB
MSTO
WDs
Red
Dwarfs
46
“Isochrone”
Red Giant
Branch
C
More
metals
Age
B
Stellar
Populations
One line means:
same age
same metallicity
same distance
 same small cloud
A
More
Helium
“test of good photometry”
47
Omega N6397 47T
Omega Cen
NGC6397
47 Tuc
Extra
sequences
48
Plan
(1) Globular Clusters before HST
(2) Globular Clusters with HST
(3) Globular Clusters with 25 years of HST
49
Cambridge, UK 2001
Globular Cluster or Dwarf Spheroidal?
50
Red Giant
Branch
metal
poor
Stellar
Populations
intermediate
metal rich
More
metals
Age
More
metals
More
Helium
Inversion!
Similar to
galaxies…
51
OmCen
Is Omega Cen a GC?
Could the textbook globular cluster
not be one?
47Tuc
®
N2808
N6388
N6656
52
Is Omega Cen a globular?
NGC6652
Are there any globular clusters?
Questions to answer:
1) How does the enrichment happen?
2) Why are they all so different?
3) What connection is there between
clusters and galaxies?
4) Any relevance for star formation
going on today?
NGC2808
53
Plan
(1) Globular Clusters before HST
(2) Globular Clusters with HST
(3) Globular Clusters with 25 years of HST
54
GCs with Hubble Over Time
• Set up new experiments
– Probe deeper
– Probe more broadly
• Use new detectors
– Better sensitivity, resolution
– Better filter sets
• Things move!
55
ω Centauri
Anderson et al 2002
Initial 2-seq Discovery on
Main Sequence (WF/PC2)
Bellini 2014 (WFC3/UVIS)
Latest results all over the
56
diagram! 10 Seqs!
NGC2808
D’Antona 2005 (ACS)
Initial Discovery
Bellini et al in prep
(WFC3/UVIS)
57
Motions in ω Centauri
2002 ACS H-alpha
58
Motions in ω Centauri
2015 WFC3/UVIS F606W
59
Motions in ω Centauri
2015 WFC3/UVIS F606W
MOTIONS OVER 13 YEARS
60
Proper
Motions
Important Qs
• Formation hints
• Are GCs just little
galaxies?
• Do they have mediumsized BHs?
• How did the big BHs
form in big galaxies?
61
Plan
(1) Globular Clusters before HST
(2) Globular Clusters with HST
(3) Globular Clusters with 25 years of HST
(4) Globular Clusters in the next 25 years…
62
View to the Future: the James Webb
Space Telescope
63
View to the Future: the James Webb
Space Telescope
64